The effect of Na2SO4 concentration in aqueous phase on the phase inversion temperature of lemon oil in water nano-emulsions

摘要

Lemon oil in water (LO/W) nano-emulsions were synthesized using the phase inversion temperature emulsification technique (PIT), which is used as a low-energy method to produce the samples which are stable in the long term. Tween 40 was used as a surfactant and the effect of Na2SO4 concentration on the synthesizing method i.e. PIT and the particle size was well investigated and elucidated. The particle size and distribution index of LO/W emulsion measurement were carried out using zeta potential analyzer. To compare the size and stability of nano-emulsions by variations in temperature and time, the transmittance percentage of prepared nano emulsions with different concentrations of Na2SO4 was determined by spectrophotometer UV-Vis at a wavelength of 600 nm. According to the results, with increase in Na2SO4 solution concentration from 0.05 to 1 M, a gradual reduction was observed in the PIT from 66 to 49 degrees C. The optimum temperature was also reduced with increase of Na2SO4 concentration in the aqueous phase and the optimum temperature was found to be 9 to 16 degrees C below the PIT to have the nano-emulsion with more stability. The average drop sizes for nano-emulsions with 0.25 and 0.8 mol/L of Na2SO4 in aqueous phase at 25 degrees C were 9.6 and 11.1 nm, respectively, and the dispersion index were 0.380 and 0311, respectively. (C) 2016 Elsevier B.V. All rights reserved.